1. Field of Invention
This invention relates to athletic surfaces. More specifically, it relates to a specially designed cushioned athletic surface.
2. Prior Art
In this era where fitness has become important to Americans, greater use of outdoor and indoor athletic facilities is occurring. Because of the demand for these athletic facilities and because of their increased cost of construction, it is critical that the maintenance costs of such facilities be kept to a minimum.
Early athletic surfaces, particularly tennis court surfaces, were constructed from concrete, asphalt or clay. Each of these surfaces has certain significant deficiencies. Clay surfaces, while soft and easy to play on, are expensive to install and difficult to maintain. Asphalt and concrete are unyielding surfaces which frequently cause injuries. In addition, concrete and asphalt surfaces, when exposed to extremes of heat and cold and to water and ice, frequently crack or split, thus making them less useful and subject to constant repair.
As a result of these deficiencies in the bases most frequently used for athletic activities, artificial cushioned surfaces have been developed. For example, there has been developed an artificial cushioned surface manufactured under the trademark Courtship by TenniSphere, Inc. in Rome, Georgia. This surface is comprised of a polyethylene foam which is glued to a spun-bond, non-woven polyester material. To these joined materials is added an SBR (styrene butadiene rubber) latex coating which is air dried in place. To this surface can be added multiple layers of a conventional acrylic latex mixture with or without sand and various paints to give the surface of the material the feel and touch of a tennis court.
While this artificial surface looks and feels like a tennis surface, it has many significant deficiencies particularly when used in geographic areas with significant year-round changes in temperature. The major deficiency in this surface results from its shrinkage when exposed to external temperatures above about 50.degree. or 60.degree. F. caused at least partially by moisture absorbency. As this surface is exposed to these changes in temperature, it shrinks approximately 0.8% in length and approximately 0.7% in width. This shrinkage frequently results in cracks in the base around the outside of the tennis court ranging in size from about 1/2 "to 2" in width. While there are methods to repair these cracks, such methods are expensive and additional cracks sometimes occur even after the repairs are completed. In addition to the shrinkage problem, this artificial tennis court surface is too soft, thus providing a less useful playing surface. Because of this softness the material wears out quickly requiring replacement in a relatively short period of time. An additional deficiency in this surface is the result of the polyethylene foam and the polyester material being glued together. Under continued use, these surfaces may come apart causing bulges or bubbles in the surface necessitating repairs to the surface. A further deficiency of this surface caused by its softness is disclosed when the material is repaired after being torn. Replacement sections create an area of the surface which will exhibit a considerably different playing feel than the rest of the surface.
A slightly improved process for the production of an artificial athletic surface has also been developed by TenniSphere, Inc. in Rome, Georgia. In this improved process the SBR latex which coats the polyester, is heat dried in place. This reduces slightly the amount of shrinkage of the surface. However, even though the width shrinkage of the material is improved by this process, the length shrinkage is not improved and all of the other deficiencies in the surface still remain, including, specifically, problems associated with moisture absorbance.
Other surfaces for use in athletic activities have been disclosed, for example, in French Patent No. 2,439,084, Eram Industries, U.S. equivalent, U.S. Pat. No. 4,337,292, U.S. Pat. Nos. 4,364,331 and 4,251,581. See also German No. 3,006,352, German No. 3,129,837, Japanese No. 3,126,953, Japanese No. 0,123,523 and Soviet Union No. 1,054,373.
Thus, the need still exists for a cushioned athletic surface which does not shrink and which has the consistent playability of asphalt or concrete courts.
Therefore, it is an object to this invention to provide an artificial athletic court surface.
It is another object of this invention to provide an athletic court surface which is not subject to excessive shrinkage.
It is another object of this invention to provide an athletic court surface which reduces the problem of moisture absorbency present in prior art surfaces.
It is a still further another object of this invention to provide an athletic court surface and a method for its production which produces a consistent athletic surface without the deficiencies of other artificial athletic surfaces.
It is a still further object of this invention to provide an athletic court surface which can be placed over existing asphalt or concrete surfaces to extend their usefulness.
These and other objects and features of the present invention become apparent to those skilled in the art from a consideration of the following detailed description, drawings and claims. The description, along with the accompanying drawings, provide a selected example of construction of the athletic court surface to illustrate the invention.